Mangano, a Republican from Bethpage, narrowed down the field of developers to two in July — the Madison Square Garden Company and Nassau Events Center, an affiliate of Forest City Ratner Companies.

Mangano identified the two proposals as “excellent” and “compelling,” adding that both companies “had the financial and managerial capacity and expertise to successfully execute a meaningful development of the Coliseum.” Regardless, he said, the decision was an unanimous one among his RFP committee.

Ratner’s company has agreed to pay Nassau County 8 percent of its gross revenue during the initial 34-year lease term, and 12.75 percent from parking fees, according to Mangano.

Nassau County will receive a minimum guaranteed payment of $4 million per year. The payments will escalate by 10 percent every five years, amounting to a minimum lease payment of $195 million for the county, Mangano said. With options, the payment can grow to $334 million.

Nassau will also receive either $400,000 per year from the entertainment outside the Coliseum, or 8 percent of the gross revenue, whichever is greater.

According to the lease, Nassau County will also maintain the rights for future development at the site.

The contract is now in the hands the Nassau County Legislature. Approval requires a simple majority, and the Legislature currently holds 10 Republicans and nine Democrats.

Mangano said the lease is signed, contains all negotiated terms and conditions, “and is immediately ready for consideration and approval.”

Forest City Ratner has agreed to accept all costs and responsibilities for operating, insuring, maintaining and providing utilities for the Coliseum beginning on Aug. 1, 2015, which is the expiration date of the county’s lease with the arena’s current operator, SMG.

Utilities alone, Mangano said, cost the county more than $2 million per year.

Beginning Aug. 1, 2015, the county will receive rent from Forest City Ratner, whether construction has begun or not.